ArcPy Not Able to Open Current Map From Stand Alone Code While Map Is Open [duplicate]

Question

Running an Arcpy stand alone script on PyScripter I followed everything in this answer to ArcPy gives error Object: CreateObject cannot open map document?

As:

1. Start up the Streets.mxd in ArcMap
   
2. Run the mxd=arcpy.mapping.MapDocument("CURRENT") inside the ArcMap (without no error)

3- Add the same mxd=arcpy.mapping.MapDocument("CURRENT") to my code in PyScripter IDE as

import arcpy
####mxd = arcpy.mapping.MapDocument(r"C:\Temp\Street.mxd")
mxd=arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd, "Layers")[0]
targetGroupLayer = arcpy.mapping.ListLayers(mxd, "Main", df)[0]
addLayer = arcpy.mapping.Layer(r"C:\Data\NetMap.gdb\Streets\OneWay")
arcpy.mapping.AddLayerToGroup(df, targetGroupLayer, addLayer, "BOTTOM")‍‍‍‍‍‍
arcpy.RefreshActiveView()
arcpy.RefreshTOC()

but I am getting this runtime error message:

Traceback (most recent call last): File "C:\Users\bhosseini\Documents\ArcPy\Trace With Graphics\module3.py", line 3, in mxd=arcpy.mapping.MapDocument("CURRENT") File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\arcobjects\mixins.py", line 625, in init super(MapDocumentMethods, self).init(mxd) File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\arcobjects_base.py", line 47, in init for arg in args)) RuntimeError: Object: CreateObject cannot open map document